Just returned a few days ago from the 15-day round trip to Hawaii. Just thought I would share my opinions regarding a couple of excursions that we took. Would be happy to answer any questions that I can.
Kona - ship's excursion - Kahua Ranch ATV Ride: this was excellent! My DH and I had a blast on the ATV's. Neither of us had any riding experience either. They even supplied cookies and s'mores after the ride. Would definitely recommend this.
Hilo - car rental: reserved through Hertz. Had a van ready and waiting at the pier. We reserved a convertible for touring Volcano National Park but the weather didn't want to cooperate. Would recommend Hertz again for the rental. Don't forget to stop at Big Island Candies!
Honolulu - car rental again and dolphin swim: went with Enterprise since they had an office close to the pier. Picked us up at Aloha Tower. Drove to Norh Shore and stopped at the Dole Plantation. The dolphin swim was done through Dolphin Quest. Very nice group of people. We got a little lost on the highway and they were kind enough to switch me to a later group. This was lots of fun and a wonderful location. We had some time before my 3:30 reservation. We had lunch on the beach at the hotel and swam in the ocean. Would recommend this also.
Kauai - ship's excursion - Kauai Lagoons golf course: I don't golf but I went along with my DH. I just drove the golf cart and took lots of pictures. This is a beautiful place! The weather was great and it was nice just spending the morning riding around the course. The weather turned really bad in the afternoon so we weren't able to see much of the island. We took a taxi to Waimea Canyon but it was socked in with clouds and rain. VERY windy also.
Maui - port cancelled due to weather.